I
read with interest Bob Orban’s comments in “A Full Bandwidth
Standard” in the Oct. 16 issue of Radio World Engineering Extra
(radioworld.com,
keyword Orban).

I
compliment Bob for joining us in our efforts to move radio technology
forward by very quickly following our lead in implementing Single
Sideband Suppressed Carrier (SSBSC) as well as utilizing an AES
connection to FM exciters in his products. Mr. Orban recognizes these
contributions by our company and has embraced them. We’re glad to
see this because it serves radio broadcasters and their efforts to
serve their listeners.

Our
intent all along has been to explore methods that bring benefit to
our industry. The Telos 10, Zephyr and Axia AoIP systems are just a
few of our innovations.

Based
upon the feedback and results so far with both SSBSC and MPX over
AES, it seems that these ideas are working, although clearly there is
more to learn! As with any tech rollout, there will always be tweaks.
We’ve made major headway in both areas in short order.

Our
initial implementation of AES composite method employs a basic
sampling rate of 192 kHz. This is by design because we intentionally
took an “off-the-shelf” approach that is “standards-based,”
which allows exciter manufacturers to implement this tech in months,
as opposed to years (again — it’s regular AES). But, we realize
that full support of the FM baseband is necessary, so Team Omnia is
hard at work creating the next version, which supports 99 kHz
spectra. When this work is done, our product will fully support the
SCA — in full digital form. Currently, our product is the
only popular processor with this capability.

Regarding
the use of a standard for MPX connectivity: Together, with Nautel, we
realized the AES3 standard
will support sampled signals up to 192 kHz. There’s nothing secret,
ad hoc or proprietary about this. All we did was route the MPX signal
into the AES3 path, and then Nautel routed that signal directly to
the modulator stage of the exciter.

This
is the digital equivalent of the analog method using an RG-58 cable,
with BNC connectors on it. Both are standard methods, as accepted by
our industry. The beauty of our choice is we are employing known and
accepted standards and methods used the world over. There is no need
to further bog down an industry by creating a need
to open yet another inquiry regarding what would be the best way to
standardize a digital MPX connection. We have one —AES3 — and our
joint efforts with the Nautel crew have proven that it works!

THE
NEED FOR DIGITAL MULTIPLEX

If
I may say so, the issue regarding a digital method for MPX was first
proposed by Omnia back in 1998. If memory serves, I seem to remember
a number of white papers written to the contrary of this concept.
Interesting how the minds of many have changed!

To
date, the MPX over AES tech has been adopted by at least three
transmitter companies, an STL company and two processing companies
besides Omnia. These are the ones of which we know of! My in-box has
inquiries from others who have interest to add the tech, and we’ll
follow up with them soon.

Again,
we are encouraged that Orban, the other popular audio processor
manufacturer is engaged with us in driving the industry forward.

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